To inject a medical solution such as an anticancer agent into the main body, for example, a catheter is percutaneously inserted into a tubular organ such as a blood vessel. Thereafter, its tip end portion is moved to reach the cancer-affected portion, and the medical solution is administered from a discharge hole disposed in the tip end portion. Alternatively, the tip end of a catheter is moved to reach a central vein, and the medical solution is administered to the whole body is performed. This kind of catheter may be provided with a valve element at a discharge hole, in order to prevent the blood or the like from reversely flowing into the catheter to coagulate therein. The valve element opens when a medical solution or the like is administered, and closes in other cases is sometimes disposed.
In recent clinical practice, in order to check whether a tip end portion of a catheter is placed in a blood vessel or not, a suction work of sucking blood from the tip end portion of the catheter may be required to thereby check whether the blood flows out from the base end side of the catheter or not (ONS Guidelines etc.). In order to perform the suction work, there is used a catheter also having a suction valve element.
As this kind of catheter, Patent Literature 1 describes a valved catheter in which an injection hole is provided with a slit valve, and a suction hole is a provided with a flap valve. The slit valve is provided by forming a linear slit in a peripheral wall portion of the catheter. The flap valve is provided by forming an arcuate slit in the peripheral wall portion. In the catheter, when a medical solution is injected into the interior and pressurized, the slit valve opens and the medical solution is injected into a blood vessel through the injection hole. On the other hand, when the interior is depressurized, the flap valve opens, and the blood is sucked into the catheter through the suction hole.
There is also known a catheter including a so-called two-way valve. In this kind of catheter, instead of providing valve elements respectively for discharge and suction as in the above-described valved catheter, the valve is configured to open both in the case where a medical solution or the like is to be discharged, and in the case where the blood or the like is to be sucked.
For example, Patent Literature 2 describes a valved catheter in which a valve including an openable slit is formed in the longitudinal direction in the distal-end side of a pipe main body having a circular cross-sectional shape. One of both edge portions of the slit of the valve is made to be easily deformable than the other edge portion when a fluid is passed from the interior to the exterior through the valve and when a fluid is passed from the exterior to the interior through the valve. In this kind of catheter, when the interior is pressurized or depressurized, the one edge portion of the slit which is more easily deformable is deformed, whereby the slit is caused to open, and a medical solution is discharged or the blood is sucked.